By the way, here's how I'm changing my code to work with the new and old
arrow interface. I'd appreciate any suggested improvements.
The old code (example):
import Control.Arrow
[...]
instance Arrow (~>) => Arrow (Bijection (~>)) where
Bi ab ba >>> Bi bc cb = Bi (ab >>> bc) (
I'm converting some code from functionally dependencies to associated types,
and I've run into a problem with equality constraints and subclasses. The
classes:
class AdditiveGroup v => VectorSpace v where
type Scalar v :: *
(*^) :: Scalar v -> v -> v
class VectorSpace v => In
All code that defines Arrow instance breaks, because (>>>) is not a method
of Arrow. I have a lot of such instances, so I'm now adding #if directives
to test for ghc-6.9 or later. - Conal
On Mon, Jul 14, 2008 at 8:38 PM, Don Stewart <[EMAIL PROTECTED]> wrote:
> conal:
> >I want to use ghc-6
On Mon, Jul 14, 2008 at 01:58:00PM +0200, Conal Elliott wrote:
> I want to use ghc-6.9 for improved support of type families, but I see that
> the change to the Arrow interface breaks some of my libraries (since (>>>)
> is no longer a method of Arrow). Will this change really be in ghc-6.9?
Yes.
Ok, the first weekly IRC meeting is scheduled for Wednesday 16 July
(tomorrow) at
1600 BST (UTC+1)
0800 PDT (UTC-7)
1100 EDT (UTC-4)
0100 Thursday in Sydney (sorry guys :-)
If it turns out to be useful, we'll make it a regular thing. See you in
#ghc on chat.freenode.net. More instruc
